1. Field of the Invention
The present invention relates to a roll feed apparatus which is suited to use in, for example, automatic manufacturing machines for manufacturing goods through a plurality of steps and, more particularly, to a roll feed apparatus of the type having a pair of rolls adapted for clamping therebetween a sheet material such as to feed the sheet material from one to another working stations.
2. Description of the Prior Art
A roll feed apparatus of the type mentioned above is proposed in U.S. patent application Ser. No. 519,174 now U.S. Pat. No. 4,549,638 filed on Aug. 1, 1983 by the same applicant. This apparatus has a first roll integrally carried by a first shaft for oscillatory rotation therewith, a second roll integrally carried by a second roll shaft for oscillatory rotation in the direction counter to that of the first roll and adapted for cooperation with the first roll in clamping therebetween a sheet material such as to feed the sheet material, a roll releasing/braking means adapted to move both rolls relatively away from each other when the rolls rotate in the direction counter to the feeding direction thereby unclamping the sheet and having first and second braking members, the first braking member being adapted to be moved towards the second braking means such as to temporarily fix the sheet when the sheet is unclamped, and an adjusting means for moving the first braking means towards and away from the second roll thereby optimizing the gap between the rolls for the sheet to be fed in accordance with the thickness of the sheet to be rolled.
In the roll feed apparatus of the preceding application mentioned above, the movable first braking member is moved towards the stationary second braking member thus clamping the sheet between these braking members thereby temporarily fixing the sheet therebetween. This arrangement incorporating one movable braking member and one stationary braking member, however, encounters a problem in that the fixing of the sheet by these braking members cannot be made satisfactorily when the thickness of the sheet which is clamped and fed by both rolls is changed.